In this application, the PI will explore the hypothesis that the anterior temporal lobes (ATL) are part of a neuronal network supporting social cognition and that they are specifically engaged when tasks demand access to social knowledge. Anatomical evidence from tractography and cellular studies, and functional evidence from ablation and neuroimaging studies, all indicate that portions of the ATL play some role in social cognition. More direct evidence that this region plays a specific role in processing social knowledge can be found in recent fMRI studies showing sensitivity to social semantic detail, and overlapping ATL activations to disparate tasks whose only similarity is their underlying social semantic structure. In this proposal, fMRI experiments are proposed that will examine three interrelated aims. The goal of Aim 1 is to validate the social knowledge hypothesis by assessing the specificity and generality of the ATLs sensitivity to social knowledge while simultaneously testing competing hypotheses. Aim 2 will map the topographic organization of this region to better understand its social and semantic functions. Aim 3 will extend findings in adults to the developing brain by assessing the neural underpinnings of social knowledge in adolescents. If funded, these studies promise to shed new light on the functionality of a rather enigmantic brain region, the ATL, and also to clarify its role in social cognition at different points in development. Because abberant social cognition is a hallmark of several psychiatric and neurological diseases, the experiments outlined in this proposal have implications for several diseases, including frontotemporal dementia. PUBLIC HEALTH RELEVANCE: Problems in comprehending and interacting with the social world underlie many psychiatric and neurological disorders. In this grant we propose experiments that will study a novel hypothesis that a part of the brain called the anterior temporal lobes, are involved a specific component process of social processing: storing and retrieving social knowledge. The knowledge gained from these experiments will be helpful in understanding the social deficits that accompany some forms of frontotemporal dementia as well as in understanding difficulties in acquiring social knowledge that accompany developmental disorders such as autism.